1. Field of the Invention
The present invention relates to a disk device for moving an arm which supports a head and for positioning the head in a desired position.
2. Description of the Prior Art
Generally, a CSS (Contact Start Stop) system is applied to presently used magnetic hard disk devices. In this system, when a magnetic hard disk is stopped, a magnetic head is in contact with a disk surface, and the magnetic head is lifted in accordance with the rotation of the disk.
U.S. Pat. No. 4,933,785 discloses an N-CSS (Non-Contact Start Stop) type magnetic hard disk device. In the device, a cam follower member is provided inside a head slider on a surface, on a disk side, of a head support suspension of a rotary actuator assembly (i.e., on an actuator coil side), and a cam surface assembly is provided in the vicinity of an outer peripheral portion of the disk. During the unloading, the rotary actuator assembly is moved outside the disk and the cam follower member is brought into contact with the cam surface. Thereafter, the rotary actuator assembly is moved along the cam surface and is held stationary in a lock position.
Also, U.S. Pat. No. 5,027,241 discloses an N-CSS type magnetic hard disk device. In this device, a cylindrical loading tab is provided at a tip end of a head supporting suspension of a rotary actuator assembly, and a loading slant structure is provided in the vicinity of an outer peripheral portion of the disk. During the unloading, the rotary actuator assembly is moved to outside of the loading slant structure and the loading tab is brought into contact with the slanted surface of the loading slant structure. Thereafter, the rotary actuator assembly is moved along the slant surface and is held stationary in a parking region.
The Japanese Mechanical Association (No. 900-52) Lecture Paper (1990, August 23 and 24, Tokyo, Mechatronics), 204, entitled "The Load/Unload Dynamics for In-line Type Flying Head Systems in Magnetic Disk Storage" shows measurement examples relating to the contact/non-contact in an N-CSS system. In the measurement examples, however, the load/unload operation of the slider is carried out by an arm which carries a suspension. This system is different from that of the present invention. Also, the paper shows the measurement examples in which it was measured whether or not the slider was brought into contact with the disk surface at a loading speed of 80 mm/s and 40 mm/s and at an unloading speed of 5 mm/s. However, the paper is silent with respect to the preferable numerical range. With respect to the posture of the slider, the paper describes that it is preferable for the non-contact loading to adapt the case where the pitch angle is zero or positive, but does not disclose a specific measure at all as to how the positive pitch angle is attained.
In the conventional CSS magnetic hard disc device, liquid contained with the device would adhere to the disc surface so that an attraction phenomenon (stick). In order to avoid this, a texture which roughens the disc surface is formed, but this is opposite to the basic demand that the magnetic head should be close to the magnetic film of the disc as much as possible and is also contradictory to the future demand that the recording should be carried out at higher and higher density.
Also, in the N-CSS system disclosed in the above-described U.S. Pat. No. 4,933,785, the cam follower member is provided inside the head slider, and therefore, during the unloading, a large force is necessary to lift up the head slider.
Also, if the cylindrical loading tab is used as shown in the above-described U.S. Pat. No. 5,027,241, the sliding area with the loading slant structure is increased. As a result, contamination due to the wear powder or the like would occur. Also, the loading tab is made cylindrical, it is necessary to enhance the positional precision of the loading slant structure.
Also, in the loading and unloading of the conventional N-CSS type magnetic hard disk drive, as shown in FIG. 41, a leading end LE of a head slider 12P mounted through a flexure 10P on a suspension 8P is provided closer to the disk 40 than a trailing end TE. Accordingly, it takes such an angle/posture that the leading end LE is projected toward the disk surface earlier than the trailing end TE. Namely, since the leading end LE of the head slider 12P is closer to the disk 40 than the trailing end TE, a dynamic pressure would hardly occur between the disc 40 and the head slider 12P, and the disk 40 would be likely to contact (collide) with the head slider 12P.